The present invention relates to an authentication device, an authentication method and an authentication program that authenticate a timestamp about a file uploaded onto a network.
An electronic document is easy to be copied and falsified, and therefore a variety of authentication methods for verifying its validity are proposed.
For example, such a system is known that a requester transmits a hash value of an object document to an authentication server, and this hash value is registered together with a timestamp, thereby verifying that the very electronic document exists at this timestamp, i.e., that the electronic document is not falsified since this timestamp (refer to Non-Patent document 1).
Proposed further is an electronic voting system enabling judgment as to whether a post-bidding document is falsified as compared with a document at a bidding time by generating and sending a hash value of a bidding document to an certification authority (CA), and the hashed document together with a certificate of the CA is opened to the public on the Internet.
Non-Patent Document 1
Timestamp authentication Configuration Package, 2003 SEIKO Precision Inc. [Searched on May 12, 2003]Internet <http://www.seiko-p.co.jp/systems/time/stamp_m.html>
Patent Document 1
Japanese Patent Application Laid-Open Publication No. 2001-147984